1. Field of Invention
The present disclosure relates to downhole pumping systems submersible in well bore fluids. More specifically, the present disclosure concerns recirculating a portion of the flow pumped by a submersible pump of a downhole pumping system to the intake of the pumping system.
2. Description of Prior Art
Submersible pumping systems are often used in hydrocarbon producing wells for pumping fluids from within the wellbore to the surface. These fluids are generally liquids and include produced liquid hydrocarbon as well as water. One type of system used in this application employs an electrical submersible pump (ESP). ESPs are typically disposed at the end of a length of production tubing and have an electrically powered motor. Often, electrical power may be supplied to the pump motor via wireline. Typically, the pumping unit is disposed within the well bore just above where perforations are made into a hydrocarbon producing zone. This placement thereby allows the produced fluids to flow past the outer surface of the pumping motor and provide a cooling effect.
In some situations the submersible pumping systems are disposed in a wellbore where the pump intale is below the perforations. In this situation, fluid flowing from the producing zone reaches the pump inlet before passing by the motor. As such the produced fluid is pumped to the surface without first cooling the motor. To provide cooling to the pump motor, an ESP system may comprise multiple pumps and a recirculation line that directs flow from the discharge of a lower pump to below the motor.